New York City Mayor Michael Bloomberg speaks while standing with survivors and family members of gun violence at a press conference at City Hall. / Seth Wenig, AP

by Michael Bloomberg , USA TODAY

by Michael Bloomberg , USA TODAY

The slaughter of 20 innocent children and the six adults who tried to save them in Newtown, Conn., marked a turning point in our national consciousness. For more than a decade, both parties in Washington have mostly looked the other way when mass shootings occur. And they have mostly ignored the 34 victims who are murdered with guns every single day.

This is different. There is no looking away from the murdered children at the Sandy Hook Elementary School. There is no ignoring the anguish felt by their parents and by the families of the six teachers and administrators who were killed. And there is no escaping the fact that we must do more to protect our communities from gun violence.

Sunday night, President Obama said he would use whatever powers his office holds to address this violence. He should begin immediately by sending a legislative package to Capitol Hill that the new Congress can consider and vote on as its first order of business when it convenes in January. The package should have three main elements:

First, it should prohibit the manufacture and sale of the military-style assault weapons and high-capacity ammunition clips that have been used in too many mass shootings, including in Newtown. The previous ban on assault weapons expired in 2004. While President George W. Bush supported reinstating it, Congress never acted. The time has plainly come. Banning these weapons and ammunition does not mean there will never be another mass shooting. But these weapons were designed for mass killing, not hunting or self-defense. They do not belong in our communities.

Second, the president's legislative package should fix the broken background check system. Currently, nearly half of all gun sales in the U.S. are conducted without a background check. Criminals, the mentally ill, minors and domestic abusers are all prohibited from purchasing guns, but they all can do so as easily as attending a gun show or going online. The check takes only a few seconds, and it doesn't infringe on anyone's rights. That's why polls show that more than 80% of gun owners support a change in law to require background checks for all gun sales.

Fixing the background check system also requires the federal government to compel states to submit all necessary records on felons, domestic abusers, the seriously mentally ill and others to the background check system. Right now, far too many records are not in the system, which allows dangerous people -- including the Virginia Tech shooter -- to pass the background check and buy guns.

Third, the president's legislative package should make gun trafficking a felony. Gun rights advocates agree that penalties for illegal use and possession of guns should be stiffened -- and so should penalties on those who are engaged in gun trafficking.

If the president is committed to using the full powers of his office to address gun violence, there are several others steps he could and should take immediately -- steps that do not require congressional approval.

The president should make a recess appointment to fill the vacancy at the top of the Bureau of Alcohol, Tobacco, Firearms, and Explosives (ATF), which has been without a director for six years. The country would be outraged if the Department of Homeland Security went six years without a confirmed director. Leaving the ATF without a director is also a public safety threat.

Obama should direct the Justice Department to step up its prosecution of gun criminals who try to buy guns. In 2009, 71,000 people who had been convicted of gun crimes tried to buy guns by lying on their background checks. Yet the federal government prosecuted only 77 of those cases. That's one-tenth of 1%. These are gun criminals trying to buy guns illegally -- and the federal government is letting them walk.

The president should direct the Justice Department to crack down on rogue gun dealers. The vast majority of gun dealers are responsible and law-abiding. But a few bad apples help fuel the trafficking of illegal guns. Stepping up enforcement of them would save lives.

Taken together, these and other steps would make our communities -- including our schools, malls and movie theaters -- safer. And all are consistent with the Second Amendment.

In New York, we have some of the toughest gun laws in the country, and that's one reason why we're the safest big city in the nation. But even one murder is too many. If President Obama and Congress fail to lead, 48,000 Americans will be killed with guns over the next four years.

This time must be different. We cannot let this moment pass. We cannot fail our children again.